Silicon-Dominant Anode Additives for Swelling and Conductivity
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Solution Overview
Problem
Conventional battery anodes, particularly those dominated by silicon, face challenges such as high cost, inefficiency, and limited cycle life due to large volume changes during lithiation and delithiation, leading to electrical isolation and capacity loss.
Innovation Solution
Incorporation of silosilazanes, silosiloxanes, and siloxanes as additives in silicon-dominant anodes, which enhance electrical conductivity and protect the silicon surface through a high-temperature pyrolysis process, forming self-assembled patterns that absorb strain and reduce swelling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon-dominant anodes are used to increase capacity, then battery energy density is improved, but volume expansion and pulverization occur during cycling
Solution Approach 1:
The patent applies preliminary action by pre-coating silicon particles with a protective layer containing silosilazane, silosiloxane, and siloxane compounds before assembling the battery. This protective layer is formed in advance to prevent pulverization and volume expansion that would otherwise occur during subsequent lithium insertion/extraction cycles, thereby maintaining structural integrity while enabling high capacity
Solution Approach 2:
The patent uses composite materials by combining silicon particles with a protective coating layer containing specific compounds (silosilazane, silosiloxane, and siloxane). This composite structure allows the silicon core to provide high capacity while the protective coating maintains structural integrity during cycling, resolving the contradiction between capacity and strength
2Strength
If conventional anode materials are used to maintain structural stability, then anode strength is preserved, but battery cost increases and efficiency decreases
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition of the protective coating layer. Specifically, it uses compounds with silicon-to-nitrogen ratios between 2:1 and 10:1 and controlled water content (0.1-10% by weight), which optimizes the coating's ability to maintain structural stability while simplifying the manufacturing process compared to conventional complex coatings
Solution Approach 2:
The patent applies local quality by creating a protective coating with specific local chemical properties on the silicon particle surfaces. The coating has localized regions with different silicon-to-nitrogen ratios and water contents that provide tailored protection against pulverization while maintaining overall manufacturing simplicity
3Quantity of substance
If silicon anodes undergo volume changes during lithiation/delithiation, then battery capacity is achieved, but electrical isolation and capacity loss occur
Solution Approach 1:
The patent uses an intermediary substance approach by introducing silosilazane, silosiloxane, and siloxane compounds as intermediate protective layers between the silicon particles and the electrolyte. These intermediaries maintain electrical conductivity during volume changes while allowing lithium insertion/extraction, preventing electrical isolation that would otherwise occur
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Improves anode conductivity, reduces swelling, and enhances cycle life by maintaining electrical contact and reducing capacity loss, resulting in higher performance and efficiency of silicon-dominant batteries.
Implementation Method 1
The use of silosilazanes, silosiloxanes, and siloxanes as additives in silicon-dominant anodes, synthesized through specific chemical processes and incorporated into the anode slurry to enhance conductivity and protect the silicon surface
Implementation Method 2
The addition of these additives significantly improves anode conductivity
Data Source
AI summary
Systems and methods for silosilazanes, silosiloxanes, and siloxanes as additives for silicon-dominant anodes in a battery that may include a cathode, an electrolyte, and an anode active material. The active material may comprise 50% or more silicon as well as an additive including one or more of: silosilazane, polysilosilazane, silicon oxycarbides, and polyorganosiloxane. The active material may comprise a film with a thickness between 10 and 80 microns. The film may have a conductivity of 1 S/cm or more. The active material may comprise between 50% and 95% silicon. The active material may be held together by a pyrolyzed carbon film. The anode may comprise lithium, sodium, potassium, silicon, and/or mixtures and combinations thereof. The battery may comprise a lithium ion battery. The electrolyte may comprise a liquid, solid, or gel.